Thirteen individuals who are now ex-workers with Swift & Co. have pleaded guilty to immigration violations, following the government's raids last December. The sentences range from six months to a year, according to the U.S. Attorney's Office. In all, the government's raids involved six Swift plants nationwide, and involved arresting more than 1,200 immigrant workers.

The raid triggered accusations that the individuals used fraudulently obtained identification papers that presented them U.S. citizens in order to gain employment at a Swift plant in Cactus, Texas. Another worker was sentenced to eight months for using a false social security number, also to secure a job, reports the Associated Press.

In all, 53 people have been charged in the Northern District of Texas. Four remain uncharged, but that's scheduled for later this month.

No charges have been filed against Swift, reports